Asbestos fabric



JulylS, 194-1. E. H. FOSTER ASBESTOS F ABRIC Filed July 27, 1940 INVENTOR.

BOUT/446A! Far/27? BY g 2 :2 z

ATTORNEY pliable than ably chine which isadapted to produce a fabriohaving Patented July 15, -1941 UNITED. STATE PATENT OFFICE,

ASBESTOQ FABRIC Bontwell n. we. Maplew United States Rubber Company,

, N; 1., we; to liew York.

N. 1., a corporation of Jersey- Application July 21, mo, Serial No. 347,872

ll-dlaims. wt 86-193) The present invention relates to, a knitted firerepellent asbestos fabric which is much softer and more pliable than the woven asbestos fabrics provided heretofore.

Attempts have been made heretofore to provide fire .protecting clothing to be worn by firemen, forest fire fighters, welders, steel mill and fountdry workers" and others, by'j' constructing such clothing of woven asbestos fabric.v These Prior attempts, however, havebeen far frompsatisfacable heretofore. It is also softer and more pliable, can be tailored easily, drapes well and will 16 increase the comfort and emciency of the wearer.

tory because when such fire protecting clothing is made of the woven asbestos fabric available 'heretofore, the clothing has been so harsh and still that it is uncomfortable to wear and greatly interferes with the movement of the wearer.

"The present invention seeks to provide a firerepellent asbestos fabric which is more soft and the asbestos fabrics available heretofore so that rial will impede the. movement of the arms. legs and body of the wearer much less than asbestos fabric employed heretofore, and at the same time will afford a greater degree of resistance to heat than the prior fabrics of corresponding weight. The asbestos fabrics employed heretofore in fire protecting clothing were usually woven with a plain weave so that each warp yarn passed over one weft yarn'or pick and under the next weft yarn. This resulted in a maximum number of intersections of warp and weft yarns which tends to produce a stiff, boardy fabric entirely unsuited.

for clothing. The present invention contemplates a knitted fire repellent asbestos fabric formed. of knitted asbestos yarns and laid-in asbestos strands which are so assembled that there is no'strain or tension upon the finished fabric, with the result that a soft and pliable fabric knitted upon both faces and of good wearing quality and insulating properties is mined.

The fabric of the present invention in its preferred construction comprises a central layer of laid-in asbestos strands which are firmly held in parallel relation to each other by knitted loops of asbestos yarns that form a soft knitte surface upon each face of the fabric., As a resul of this construe on the fabric is suiilciently thick to afford good eat resistingproperties and the knitted face and back cause both surfaces to be soft and v smooth.

The present fabric may-be produced en different types of knitting machines but is preferformed on ,a fiat work warp knittingm'aclothing formed of this new mate- It is also well adapted for use in other fields than wearing apparel. v

The above and other features of the present 7 invention will be more fullyunderstood from the is following description when read in connection the present invention;

with the accompanying drawing, wherein:

1 is a vertical transverse section through the main portionof a warp knitting machine which is well adapted to produce the fabric of Fig. 2 is a top plan view showing the rows of needles diagrammatically and the laying-in mechanism in its forward position;

Fig. 3 is an enlarged perspectiveview of the as present fabric showing how the yarns are knitted about the laid-in strands;

Fig. 4 is a plan view of one face of the fabric of Fig. 3;

Fig. 5\is a plan view of the opposite face of this fabric; and

Fig. 6 is an enlarged perspective view of a modified form of laid-in strand.

While as above stated the fire-repellent asbestos fabric of the-present invention may be as knitted upon different types of knitting machines,

= cause of the ability of this machine to provide it is believed that a warp knitting machine is particularly well adapted to knit the same-bea laid-in fabric having smooth knitted faces.

bar warp knitting machine of well known construction and having one oscillating guide bar provided with the usual thread guides, since this machine is simple in construction and operation f to produce upon each face of the fabrics knitted 1 surface closely resembling that of the well known plain knit fabric. Such a machine, however, should be provided with laying-in mechanism for f placing the laid-in strand between the front and back rows of. needles adjacent the knitting position.

In this preferred knittingmachine there are two needles, one front and the other back for :each warp end, and each warp end is so manipueach face thereof constructed so as to: closely sini-j so lated by the oscillating guide bar as to form a The machine used is preferably a two-needle I loop first von one face of. the fabric and then on the other face' thereof. The operation is preferably such that each warp end is confined to a single vertical wale, and the knitted loops of yarns are interlocked about the laid-in strands to thereby firmly hold these strands in spaced parallel relation to each other. These laid-in strands in turn may provide the sole means for,

retaining the rows of vertical wales in close parallel relation to each other. It will be understood, however, that a. much more elaborate knitted construction may be usedif desired by employing a warp knit machine having two or more oscillating guide bars and by operating such bars in any one of a number of well known sequences. a

The yarn Y to be knitted in accordance with the present invention is an asbestos yarn preferrear of the machine and at-ap'proximately the level of the knitting position. Means not shown,

is provided for reciprocating the slide l9-to carry the strand S back and forth at the rear of the needle beds and frontwardly against the needles.

The slide I9 is shown as provided with the tubular guiding finger 2| adapted .to move frontwardly to present the strand S in the desired knitting position. The finger 2| is normally held in its rearward position clear of the raised needles by means, not shown, and is moved frontwardly ably not heavier than a cut/l yarn, and the laid-in strand S is preferably formed of one or more asbestos rovings to provide a strand thatv has a weight at least as heavy as 10 cut, and which is much softer and more bulky thanthe asbestos yarn.

The knitting machine employed to produce the present fabric may be an 18 gauge machine or finer; that is it may have at least 12 needles to the inch in both the front and rear needle bar. The warp knitting machine illustrated in the drawing is of well known construction and may be operated in a well known manner, and is shown 'as provided with two flat vertical plates 10 and II spaced a slight distance apart to form a fabric receiving passage therebetween, and they serve also as knock-over plates. 0

There is mounted adjacent. the front plate It the front needle bed l2 provided with the needles l3, and adjacent the rear plate ll is-mounted the rear needle bed 14 providing with the needles l5. These needle beds I2 and M are supported for vertical sliding movement and are operated by cam mechanism (not shown) so that one set of needles is raised to receive a warp end'oryarn in each needle hook and then is lowered, whereupon the other needle bed is similarly operated to receive a warp end or yarn in each needle hook. The warp ends or yarns Y may be supplied by the warped beam 16, there being one yarn Y for each front needle I3.

Above the rows of needles :3 and I5 there is mounted in the construction shown, a single oscfllating guide bar |'|,'provided with the thread guides l8. There is one thread guide It for each front needle l3 and its aligned rear needle IE, it being understood that the guide bar ll serves both sets'of needles to present the yarns Y first to the forward set of needles'and then to the rear set of needles as each set of needles is raised.

The sequence in which the guide bar is actuated may be varied, but the sequence employed to produce the fabric illustrated in the drawing is ormay be as follows which is well known: As-

upon reaching the end of its travel lengthwise of the needle bed. In this manner the finger II is operated to present the laying-in strand 8 to the knitting position between the front and rear row of needles without interfering with said needles. The laying-in strand 8 may be drawn upwardly from asouree of supply such as a. cone 22.

After the thread guides i8 have been operated as above described to engage the yarns Y with the hooks of theraised front needles If, they may be similarly operated to engage the yarns Y with the rear needles i5 when the latter are'raised. In this case afterthe thread guides l8 have been moved rearwardly to lay the yarns Y diagonally across the raised rear needles, the guide bar I! is shifted lengthwise in the opposite direction sufiicient to restore it to its-original position to thereby place these yarns in the hooks of the rear needles l5.

This sequence. of operations may be contlnued throughout the knitting. 'of the entire fabric and serves to place two strands of yarn, forming the two legs 23 and 24 of a knitted loop 25 between the adjacent laid-in strands S, and to form the loop 28 at the opposite face as will be apparent from Fig. 3 of the drawing. It. should be noted, however, that while the loops '2 and 26 at the opposite faces are similar in formation, there is a third strand 21 a1; theface of the fabric shown in Fig. 5 which pases through the loop 26. This strand 2'! bridges two laid-in strands S as shown and extends from one course to another.

The loops thus formed at the opposite faces of the fabric are interlocked about the strands ;S-to' prevent slipp e between the knitted and laid-in portions of the fabric. The resulting fabric is somewhat similar in construction and appearance at its two faces as will appear from Figs. 4 and 5, and causes each face of the fabric to resemble in knit fabric.

The laid-in strands S may be formed of a single asbestos roving or two or more asbestos rovings, and is preferably provided with a small strengthening yarn or thread C such as cotton disposed near the center of thestrands S to. facilitate its handling, as shown in Fig. 3. In some cases it may be desirable to further strengthen the strand S by providing along the same an asbestos thread T such as one end of 30 cut 2 or 20 cut 2 asbestos yarnor thread which may become. more or less embedded in the roving S as shown in he modified construction of Fig. 6.

In order that the construction of the fabric of the present invention may be further understood, the table that follows gives one good practical appearance the face of a plain amount of yarn form the knitted surface of both faces of the fab-- ric and connections therebetweenis largely responsible for the desirable features of the presthe' practice to mix various fl- 75 Team bers or filaments with asbestos fibers to impart increased strength to the asbestos rovings or strands It is herein contemplated that the yarns Asbestos cloths for fire repellent clothing and other uses New (knitted) I ld (woven) 1 Wales rin "1 13 warps rin 2 Course per in -9. 6 Wefts p 1 in-.. -10. 4 3 Laid-in strands per in. 9. 6 Plain weave. .l and l 4 Knitted yarn material- .ifl l cutll Vin Warp material- ..--15. 4 cut/2, am ro 5 Laid-in material W }Weft material .14. a cut/2 6 01s. sq. yd 17.0 wt. Ozs. sq. -.28. 8 wt. 7 Gauge oiiabric 075" Gauge of is ric 062" 8 Strength lengthwise (Grab test-1")-.9l lbs. Strength warp Grab test-1") 128 lbs. 9 Strength crosswise (Grab test1'?) ..88 lbs. Strength welt rah test-3 ..64 lbs. 10 Compzessibility under a load of 5 lbs./m Compgessibility under al of 5 lbs./

sq. sq ll Yds. of knitted yarn required, in the ,Y'ds of yarn in warps to form 1 sq. yd.

lengthwise direction of the fabric, to of fabric "850 make 1 sq. yd. of fabric "3220 i The gauge of the fabric was measured by an automatic micrometer having a pressure foot of an inch in diameter and actuated with a constant pressure of 6 ounces 1 The compressibility was determined by a micrometer provided with a pressure foot having an area of one square inch and adapted to exert an initial p The fabric of the present invention is much better adapted for use in the construction-of fire added load oi five pounds was measured with reference to the thick 'ressure on the fabric of 6 ounces,

able heretofore, and possesses pronounced advantages in other fields of use. For example ness under an initial tos fiber.

and the compremibility under and of 6 ounces.

Y and strands S will contain at least 10% asbes- Having thus described my inventionpwhat I claim and desire to protectby Letters Patent is: 1. A knitted fire-repellent asbestos fabric which is much softer and more pliable. than a woven asbestos fabric has been used heretofore as a reinforcement for molded products and to produce laminated constructions. It is found that the present the contour of molds or .forms much better than a woven fabric, and that its: increased softness and greater compressibility are desirable properties in this molding field;

when the present nated constructions such for example as nonmetallic gears, to secure a desired thickness. itis found that it provides a saving in asbestos ma-V terial by weight over a woven laminated construction of the corresponding thickness since the present fabric is less compact than the usual woven asbestos fabric and requires from 25 to 33% less material for a given thickness of fabric. In either laminated or molded constructions the present fabric ,can be irregular objects without the formation of wrinkles, which is a further advantage over woven asbestos fabrics.

A still further advantage of the present soft flexible fabric resides in its improved heat resistant properties over a woven asbestos fabric of corresponding thickness.

It will be apparent from the drawing that the laid-in strands S are disposed in straight parallel relation at the center of the fabric where they em fabric.

It is r u y fabric is employed in lamishaped about rounded or knitted fabric will conform to soft knitted surface upon interlocked about said strandsand forming a woven asbestos fabric of the same weight per square yard, comprising a central layer of laidin asbestos strands, and knitted loops of yarns interlocked about said strands and forming a I both faces of the fabric, said knitted loops being formed of asbestos yarns not heavier than a 20 cut/1 yarn and knitted with at least 12 wales to the men upon each face of the fabric.

2. A knitted fire-repellent asbestos fabric which is much softer and more pliable than a woven asbestos fabric of the same weight per square yard, comprising a central layer of laidin asbestos strands, and knitted loops of yarns interlocked about said strands and forming a soft knitted surface upon both faces of the fabric, said knitted loops being formed of asbestos yarns not heavier than a 20 cut/1 yarn and-together with said laid-in strands forming a fabric over .050"

thick. a 3. A knitted fire-repellent asbestos fabric which is much softer and more pliable than a woven asbestos fabric of the same weight per square yard, comprising a central layerof laid! in asbestos strands, and knitted loops of yarn:

knitted surface upon both faces of the fabric, said knitted loops being formed of asbestos yarns not heavier than a 20 cutll yarn, and said laidin strands having not less than twice the weight per yard length assaid knitted yarn.,

4. A knitted fire-repellent asbestos fabric which is much softer and more pliable than a,

woven asbestos fabric of the same weight per square yard, comprising a central layer or laidint'erlockedabout said strands and forming a soft heavier than a 20 cut/1 yarn, and M ther with said laid-in strands forming a fabric that is over ,.050." thick and which welghs not over 30 ounces I yard.

in asbestos strands, and knitted loops of yarns.

5. A- knitted fire-repellent asbestos fabric which is much softer and rnore pliable than a woven asbestos fabric of the same weight. per

square yard, comprising a central layer of-laid-,

in asbestos strands, and knitted loops of yarns interlocked about said strands and forming a soft knitted surface upon both faces of the fabric, said mamas-o knit construction and forming a soft knitted v surface upon both faces of the fabric, said knitted knitted loops being formed of asbestos yarns not heavier than a 20 cut/l yarn, and the compressibility of said fabric being approximately 19 per cent at 5 pound load.

6. A knitted fire-repellent asbestos fabric which is much softer than a woven asbestos fabric of the same weight per square yard, comloops being formed of asbestos yarns not heavier than a 20 cut/1 yarn.

9. A warp-knit, fire-repellent asbestos fabric which is much softer than a woven asbestos fabric of the same weight per square yard, comprising a central layer of laid-in asbestos'strands,

and knitted loops of yarn interlocked by a warp knit construction to thereby form a close simulation of a plain knit construction upon each face of the fabric, said knitted loops being formed of asbestos yarn not heavier than a 20 cut/ 1 yam.

10. A warp-knit, fire-repellent asbestos fabric which is much softer than a woven asbestos fabric of the same weight per square yard, comprising a central layer of laid-in asbestos strands,

' and knitted loops -,of yarn interlocked by a warp ing a central layer of laid-in asbestos strands,

and knitted loops, of yarns interlocked about said strands and forming a soft knitted surface upon both faces of the fabric, said knitted loops being formed of at least 2,000 yards of asbestos yarn per square yard of said fabric.

8. A warp-knit, fire-repellent asbestos fabric which is'much softer than a woven asbestos fabric of the sameweightper square yard compris ing a central layer of laid-in asbestos strands, and knitted loops of yarn interlocked by a .warp

knit construction to thereby form a close simulation of a plain knit construction upon,.each face of the fabric, said knitted loops being formed of at least 2,000 yards of asbestos yarn per square yard of said fabric.

11. A" knitted fire-repellent asbestos fabric which is softer than a woven asbestos fabric of the same'weight per square yard, comprising a central layer of laid-in soft, compressible strands formed of asbestos rovings reinforced with asbestos yarn, and knitted loops of yarns interlocked about said strands and forming a soft knitted surface upon both faces of the fabric, said knitted loops being formed of asbestos yarns much smaller than said laid-in strands.

BOUTWELL H. FOSTER. 

